This invention relates to dust collectors for industrial sewing machines, and more particularly to an improvement of a dust collector which can collect waste threads and rags separately.
During a sewing operation with an industrial sewing machine, especially an edge sewing machine, waste threads and cotton dust (hereinafter referred to as "waste threads") are created by the cutting of sewing threads, and pieces of small useless cloth (hereinafter referred to as "waste rags") are also created. These waste materials not only detract from the working environment but also may put the sewing machine out of order at least reduce its efficiency if they get into the sewing machine mechanism. Therefore, a dust collector has heretofore been provided for an industrial sewing machine.
In one example of a conventional dust collector for an industrial sewing machine, as shown in FIG. 1, a blower 12 is coupled to the free end of the rotor shaft of a clutch motor 10 which is the main drive source of the sewing machine, so that the blower 12 is driven by the motor rotor to apply a negative suction pressure from the blower 12 to a dust collecting box 16 through a suction hose 14. A relatively small diameter suction hose 18 and a relatively large diameter suction hose 20 are connected to the dust collecting box 16 for suction of mainly waste threads and waste rags, respectively, and the other ends of these hoses 18 and 20 are extended to waste material creating places in the sewing machine. A discharge hose 22 is connected to the discharge side of the blower 12, and its other end is open to the atmosphere.
In the conventional dust collector, as the blower 12 is rotated, the air flows in the dust collector as indicated by the arrows, as a result of which waste threads and rags are sucked into the dust collecting box 16 through respective suction hoses 18 and 20. In this operation, since the velocity of the air is decreased abruptly when it reaches the dust collecting box 16, the waste threads and rags are dropped onto the bottom of the box 16, and only the air is discharged through the blower 12.
In the conventional dust collector, the suction hoses for waste threads and rags are different in diameter and are connected to a single dust collecting box as described above. In order to suck in waste threads, the diameter of the first suction hose 18 is made small to increase its suction pressure, while the diameter of the second suction hose 20 is made large so that the suction hose 20 may not be clogged up with waste rags. However, increasing the diameter of suction hose 20 may result in a decrease in the suction pressure of suction hose 18.
Therefore, in the conventional dust collector, sometimes creating a sufficient suction negative pressure in the suction hose 18 is not compatible with preventing the suction hose 20 from being clogged up with waste rags, and in the conventional dust collector it is common for either the suction negative pressure to be insufficient or for the suction hose to be clogged up with waste materials.